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Original Filed March l, 1920 Y May 2s, 1929.

May 2s; 1929. y H' 1- SWANSON- Re. 17,311

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UNITED STATES riait or omo.

ing machine in which' the work is supported and rotated and may be movedaxially without the aid of positively driven work sup-y porting centers,and the chief object ofthe invention is to provideV a structure whichwill cause a noncylindrical pieceof work to und to a cylindrical form. j

invention further consists in a ywork holder comprising blades, Vplatesor guides adapted to engage and guide cylindi'ical blanks along thegrinding surface of a ding wheel, and supporting mechanism or-the guideswhereby they vmay be rotated on an axis, parallel `to the axis of thework.

It further consists in providing a supportpermit the guides to berotated "as a unit about an axis substantially. perpendicular to theaxis of the work.

,It also consists in providing means for the wheel.

It also consists in the details of construcf A tion illustrated in theaccompanying drawings and particularly pointed out injthe Intheaccoin isa side elevation o f this im rov grinding machine with a portion ofvtable broken away to show the method of a thereto the estals for Ythegrindi wheel arbor. .2isaplan of thegrin machine. Fig. 3 isan elevationof the work i -holder orb-guide block. F' 4 is a section ontheline4--4ofFi `ig.5isafsecti0n ontheline5-5of ig.1on'alar hsiiai;

. Fig. 6 is an 'end elevation of the wo on a. scale.

Similar reference characters refer to like parts thr out the severalviews.

The grin machine is ofthe same general character as7 tha Patent No.1,106,803, granted .August. 11, 1914, to R. H. Grant, and is for thepurpose of grinding cylindricalblanks Suchas the i rollers of rollerwrist pins of enginas and other parts of whi i must be as nearly perfectcylindersas'pdssible. This machineHikethatshown in the dra visadatedtogrindthesecylindrical wi out the =ty of reviously centering them and ancantera.

This invention relates to a centerless grind a ing mechanism forl saidguides 'which willi moving this rotatable .guide toward from t shownin'- Re. 17,311 PATENT OFFICE. I

HARRY J'. SWANSON, 0F DETROIT, MICHIGAN, ASSIGNOR, BY IESNEASSIGN'HIBI'il!S, T CINCDTNATI GBINDEBB INCOBPOBATED, 0F CINCINNATI,OHIO, A. CORPBA,

GBINDEB.

.original iro. i,sa4,oos, ima December as, i920, sensi nu. assess, algaumn i, i920. applicati for reissue iled August 14, 1926. Serial No.129,894.

' the waste of the oil or other grinding liquid.v

A'carriage 4 is slidable cn the table by the screw in a well knownmanner when the The pedestal .l shown in Fig. has securedscrew is turnedby the handle 6. Projecting o up from the carriage but forming' a artthereof is a post 7 in which the shaft 8, W ich is indicated in dottedlines in Figs. 1 and 2, is rotatable. This shaft is rigidly connected tothe support ors chuck 9 for the 'de block 10. The chuck 9 has asemi-cylin 'cal bearing surface 11 provided with a dove-tail i groove 12to receive the rib 13 on the guide block. A nut ii on the shaft s V10ersthe shaft, chuck and guide block from turning."

The chuck is formed with vertical slots 15 across which the bolts 16extend andare adapted-to draw the metal on -each side of these slotstogether and thus grip the rib 13 on the guide The pedestals 18 sup rtanarbor 19 on which is mounted a' ing belt 21 and the nical grinding wheel22 which is turned in the direction of the arrow in Fig. 1. The shaft 8is substantially radial to the face of 'this'wheel and ey20 for thedriv-Y I -central groove 25 to receive the central back Y blade or guide26 whose inner edge is at right angles to its parallel sides and whichis ch` the ide block 10 by means of bo ts 30 whose are slidable -in theT-grooves 32 in the hea .guide block. The outer side of the top guideshould slant hack from the lane of the outer side 'of the bottom blade aut thirteen and one-half degrees and the'angle between its `parallelsides and its ends 83 is preferablyv .Y

lock and prevent it -from rotat- "l5 guide and the center or back guideto be about of the wheel are in the same drical grindin work iscausedtl) seventy six and one-half degrees.

Rotary movement of the guide block produces a variation in theco-'eicient of friction becaus'e of the resultant of the pressures ofthe grinding wheel and the back guide resisted by the bottom guide. Thecenter of the work and the center of rotation of the guide block shouldbe the same and the line of contact of the grinding wheel is always thesame for any position of the guide block. By turnin the guide block tothe left in Fig. 6, the riction of the work on the bottgm blade isdecreased. Turning the guide block moves the point of intersectiomof theplane of pressure between the work and wheel up and down thebearing edgeof the back guide plate.

Assuming the work to be a polygon having' a large number of sides, itwill be noticed that by turning the guide block, it will be possible toobtain a position when an angle of the polygon will contact with the'grinding wheel while a side of the olygon will contact with the end -ofthe bac guide. This will of course result in a minpte at taking theplace of the angle and further results in a polygon in which the numberof sides becomes i so great that practically perfectly round work isobtained. I have found that to obtain this perfect work, thecircumferential distance from the line of contact between the work andthe grinding wheel to the linev of contact between the work and thebottom blade should be lsuch that it cannotbe divided equally into thecircumference of the work. 4

The grinding wheel causes the work to move endwise between the blades.By turning. the guide block-.su portion ,its shaft` the: rate of this'feed may be varied, the slowest lfeed being had when the-work and thearbor lane.

The face 23 of the guide block may be formed with grooves 36 toconstitute passages for the -oil or other grinding liquid which ows tothe rotatin cylindrical work. The T-grooves 32 in this ace also servethis purpose.

It will be understood that the work support may be used in connectionwith a c linwheel since the feed o the y the screw-like action of thegrinding wheel upon the work whenV the work axis and the wheel axis donot lie in the same plane. Or it may be used in .connection with a wheelwhich has its grinding surface `on one side or at an angle between thatof a flat disk l and a c lin er.

The etails` of construction and the roportions of the parts may all bechange by those skilled in the art without departing from the spirit ofmy invention as set forth in the following claims.

I claim 1. A work holder comprising a guide block and plates adapted toengage and guide cylindrical blanks along the face of a grinding wheel,a shaft extending substantially radially to the face of the wheel and onwhich the guide block is mounted, and means rotatably supporting saidshaft, said ,means comprising a carriage movable toward and from thegrinding wheel, said. guide block being formed substantiallysemi-cylindrical and said shaft being formed with a head having asemi-cylindrical recessin which said guide block is rotatably mounted.

2. A Work holder comprising a substantially semi-cylindrical guide blockhaving an axial groove and three guide plates mounted thereon to' engageand guide cylindrical blanks along the grinding surface of a grindingwheel, the niiddle guide being at substantially right angles to one ofthe other guides which are attached to the fiat sides of the guideblock, one `on each side ofthe axial groove.

3. A work holder comprising a substantially semi-cylindrical guide blockhaving an axial groove and three guide plates mounted thereon to engageand guide cylindrical blanks along the grinding surface of a grindingwheel, the middle guide being at substantially right angles to one oflthe other guides which are attached to the flat sides of the guideblock, one on each side of thel axial groove, a shaft extendingsubstantially ra'dially of the face of the grinding wheel and on whichthe guide block is mounted, and means to rotatably support said shaft.

4. A work holder comprising a substantially semi-cylindrical guide blockhaving an axial groove and three guide plates mounted thereon.L toengage and gulde: vcylindrical blanks alon the rinding surface of arindin wheel, t e midle guide being at su stantia ly right angles to oneof the other guides which areattached to the fiat sides of the guideblock, one on each" side of the-axial groove, a shaft extendingsubstantiall radially of the face of the grinding wheei and on which theguide block is mounted, means to rotatably support said shaft, saidshaft being formed wlth a head having a semi-cylindrical recess toreceive said-guide block, and means to lock the guide block from turningin said recess.

5. In a centerless grinding machine having I a grinding wheel, means torotate the same,

- ing wheel Whiclrlies at an obtuse angle to a -e'qually into thecircumferential distance plane tangent to the Work and passing throughthe line of contact of the work and the wheel, and a.member to hold thework on the guide in operative contact with the grinding Wheel, saidsupporting guide having its operative face so related to the grindingwheel that the. circumferential distance from the line of contact of thework with said operati've face to the line of contact of the work withthe grinding wheel is not divisible around the work.

6. In a centerless grinding maehi ne having a grinding wheel and astructure to hold work inoperative relation therewith, saidstructurecomprising a supporting guide having a tace contacting with the workadjacent to the grinding wheel in such a position that the cirei'lmt'erential distance from the line ot' contact of the Work and thegrinding wheel to the line of contact. of the work and the guide is notdivisible equally into the ci rcumi'e rential distance around the work,and means to hold the work in rotative contact with said wheel andguide. Y,

7. In a centerless grinding machine having a grinding wheel and astructureA to hold work in operative relation therewith, said structurecomprising a supporting guide l1 aving a face contacting with the Workadjacent to the grinding wheel in such a position that thecircumferential distance from the line of contact of the work and thegrinding wheel to the line ot' Contact of the work and the guide is notdivisible equally into the circumferential distance around the work,means to hold the Work in rotative contact With said wheel and, guide,and means for Varying the rate of axial feed of the Work relative to thewheel.' Y

8. A work holder comprising a guide block 'and three guide platesadapted to engage and guide cylindrical blanks along the grindingsurface of a grinding wheel turning on a horizontal axis, the middleguide being at substantially right angles to the upper guide and atanangle of substantially seventy six and one-half degrees to the lowerguide.y

9. A work holder comprising a guide block and three guide plates adaptedto engage and guide cylindrical blanks along the grinding surface of agrinding wheel'turning on a horizontal axis, the middle guide being atsubstantially right anoles to the upper. guide and at an angle of sustantiallyseventy six` and one-half degrees to the lower guide, thebearing end of the middle guide being at rightmigles to its parallelsides and the bearing end of the lower guide being at an angle of:substantially forty five degrees to itsparallel sides. V

10. A work holder comprising a guide block and three guide platesadapted to engage and guide cylindrical blanks along the grindingsurface of a grinding Wheel turning on a horizontal axis, the middleguide being at substantially right angles to the upper guide and at anangle of substantially seventy six and one-half degrees to the lowerguide, the bearing end of the middle guide being at right angles to itsparallel sides and the bearing end o'l the lower guide being at an angleof substantially forty five degrees to itsparallel sides, and means tosupport the guides pennitting them to turn as a unit about the axis ofthe blanks'.

11.v A work holder comprising a guide block and three guide platesadapted to engage and guide cylindrical blanks along the grindingsurface of a grinding wheel turnl ing on a horizontalaxis, the middleguide belng at substantially right angles to the upper guide and at anangle of substantially seventy six and one-half degrees to thelower

